1 files changed, 40 insertions, 0 deletions
diff --git a/browser/components/extensions/test/browser/browser_ext_tabs_warmup.js b/browser/components/extensions/test/browser/browser_ext_tabs_warmup.js
new file mode 100644
index 0000000000..e9a5382de8
--- /dev/null
+++ b/browser/components/extensions/test/browser/browser_ext_tabs_warmup.js
@@ -0,0 +1,40 @@
+/* -*- Mode: indent-tabs-mode: nil; js-indent-level: 2 -*- */
+/* vim: set sts=2 sw=2 et tw=80: */
+"use strict";
+
+add_task(async function testWarmupTab() {
+  let tab1 = await BrowserTestUtils.openNewForegroundTab(
+    gBrowser,
+    "http://example.net/"
+  );
+  let tab2 = await BrowserTestUtils.openNewForegroundTab(
+    gBrowser,
+    "about:blank"
+  );
+  Assert.ok(!tab1.linkedBrowser.renderLayers, "tab is not warm yet");
+
+  let extension = ExtensionTestUtils.loadExtension({
+    manifest: {
+      permissions: ["tabs"],
+    },
+
+    background: async function () {
+      let backgroundTab = (
+        await browser.tabs.query({
+          lastFocusedWindow: true,
+          url: "http://example.net/",
+          active: false,
+        })
+      )[0];
+      await browser.tabs.warmup(backgroundTab.id);
+      browser.test.notifyPass("tabs.warmup");
+    },
+  });
+
+  await extension.startup();
+  await extension.awaitFinish("tabs.warmup");
+  Assert.ok(tab1.linkedBrowser.renderLayers, "tab has been warmed up");
+  gBrowser.removeTab(tab1);
+  gBrowser.removeTab(tab2);
+  await extension.unload();
+});